In the past, a honeycomb filter has been widely known as a filter for a DPF (Diesel particulate filter) or the like. The honeycomb filter includes a structure in which one end sides of a part of through-holes of a honeycomb structure including a large number of through-holes are plugged by a plugging material and the other end sides of the remaining through-holes are plugged by the plugging material. Patent Literature 1 discloses a method of producing such a honeycomb filter. In Patent Literature 1, on one end face of a honeycomb structure 1 arranged in a cylinder 7, a plugging material is pressed against through-holes by a piston 8 via a mask, in which holes are opened in plugging places, whereby the plugging material is supplied to ends of desired through-holes of the honeycomb structure.